A part of the video engine is available on linux at the moment. The part that is accesible is the mpeg2 decoding engine and it can be accessed using the XvMC extension. (note XvMC works for Geforce4 (Ti is less advanced) and GeforceFX cards too) For an application to take advantage of it, the application needs to be patched. For example xine/mplayer support XvMC but you need to enable it when you want to use it for lets say a DVD. In the future XvMC might be extended or a new extension will be developed to get access to the advanced 6800 features but applications need to be patched.